<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
abcdefg hhhh
<input type="button" value="提交">
<div style="height: 2000px;"></div>
<div style="z-index: 1;opacity: 0.5;position: fixed;top: 0;left: 0;right: 0;bottom: 0;background-color: black;"></div>
<!--loading-->
<!--<div style="z-index: 2;position: fixed;left:50%;top:50%;margin-left: -16px;margin-top: -16px;">-->
    <!--<img src="loading.gif">-->
<!--</div>-->
<div style="z-index: 2;position: fixed;left: 50%;top: 50%;margin-left: -100px;margin-top: -50px;">
    <div style="background-color: white;width: 200px;height: 100px;">
        <input>
        <input>
        <input>
    </div>
</div>
</body>
</html>